Mutable counter bag fed by processSyncEvent as the action consumes
the SDK's synchronize() event stream. Exposed alongside the processor so
unit tests can drive each SyncEvent variant deterministically (notably the
copy-start / copy-done events that only fire in b2-to-b2 sync, which
the action's input surface doesn't currently expose).
Mutable counter bag fed by processSyncEvent as the action consumes the SDK's
synchronize()event stream. Exposed alongside the processor so unit tests can drive each SyncEvent variant deterministically (notably thecopy-start/copy-doneevents that only fire in b2-to-b2 sync, which the action's input surface doesn't currently expose).